Jack element



Feb. 13, 1940. G GUNN 2,189,981

- JACK ELEMENT Filed Sept. 9, 1938 INVENTOR Y Earl 6. @zzn TTORNE V5.

Patented Feb.13,194o

I "Qaisaasif 1 .mcx ELEMENT Earl GunnQ Jackson; Mich, to j a Manufacturing'jcompany',,Bacine, Wis}, a' corporation of Wisconsin j I n 1 Application se temberfs, issas rie No 229,059

\ was 2 40.

This invention relates to an improvedlifting plate for friction type jacks. The invention also relates to the novel method of forming the infproved lifting plate and a unique type of tool intended for practicing the novel method.

Lifting plates of the type herein disclosed are I method 'set forth in the preceding paragraph.

primarily intended for usein frictiontypelift-t ing mechanisms such, for example, as vehicle, jacks of the type illustrated'in applicants prior co-pending. applicationserial No. 191,050, filed February. 17; 1938. i n a r-j In jack mechanisms of this general'chara'cter, the lifting plates are designedito have an apere ture therein very slightly larger than the outside 1" diameter of the lifting standard with which the plates are associated whereby, upon the tilting of the lifting plates, they will 'frlctionally engage the surface of the same. a

In applicant's prior co-pending application; a" jack mechanism is illustrated which employs a plurality of superimposed lifting plates each adapted to operate more or less independently of the other and adapted to frictionally engage the exterior surface of the standard independently of each other whereby to distribute the load throughout a relatively large number of individu-f the standard and positively grip ally separate areas. p i The utilization of a plurality of lifting plates of this general type serves not only the purpose of distributing the load but permitsthe manufacture of the plates from a relativelythin sheet metal stock whereby thesame may be stamped in an ordinary punch press from sheet metal instead of having to be forged or. otherwise formed-'2 Considerable difliculty has been experienced in the fabrication of sheet metal lifting plates of this generic type in that ina stamping operation, extremely close engineeringtolerances can-1 not be maintained and, therefore, the sharp cor-- ners of the aperture have a tendency to-scorei and deform the exterior surface of the. lifting:

column. I v

Itis a primary object of the present invention to provide a relatively simple, cheaply manufactured lifting plate structure which is preformed in such away that ithas a small but well defined area which is adapted to engage the exterior surface of the column and, therefore,

operates with maximum efficiency immediately upon installation. of the jack mechanism.

Still further, the invention contemplates the provision of a novel method of fabricating such lifting plates in such a manner that the metal around theaperture of the plate which is adapted shown-in Figure 5.

i kind.

to] engage'the lifting column' is preformed pre cisely to the desired configuration prior to 1 :the assembly of the'mechanism.

Still further; the present invention contemplates the provision of a novel form of tool constructed and arranged to practice the novel ofthepresent inventionL. i

- Figur'e'zis afragmentary side elevational view with. partsin section illustrating the manner in which the improved lifting plate is adapted to.

frictionallyl. engage a supporting column of a lifting mechanismn' t w j- Figure 3 is] an enlarged fragmentary sectional view diselosing the novel configuration of the aperture in the lifting plate when formed by the method of the present invention.

- Figure 4.is a: fragmentary transverse sectional view. offthelifting plate shown in Figure 3, disclosingr'the :same in an intermediate stage of manufacture.. a p p V f' iFigure 5 is aJtop plan view of the tool utilized for formingthe improved lifting plate structure. Figure 6 is'a-side elevational view of the tool Figure 'Iis a bottom plan viewJof the tool shown in Figuresdand 6. a

- With more particular referenceto the drawing, the lifting plate Hlillustrated inFigure 1 is of the type designed and intended for use-with friction type jacksand is of generally circular configuration exceptxforthe fact that ithas a projecting lug or ear. ll whichzis adaptedto beengagedby the plate canting mechanism in order to. cant the plate with respect rtogjthe lifting column. with which the plate is subsequently to be associated. This lifting plate is preferably formed from cold rolled steel or similar material of a thickness sufiiciently thin so that it may. be stamped to the configuration shown and as an initial stage in the operation, the liftingplate has an aperture |2 formed therein. This aperture 12 may be punched out during the stamping operation as is conventional in the formation of articles of this out roughly to the finally desired. form, the axial ends of the aperture 12 are counter-sunk as at l3 at approximately a 45 angle. The advantageand purpose of this counter-sinking operation will be readily apparent hereinafter. The lifting plate then assumes the form illustrated in Figure 4 of the drawing, and is ready for treatment by means of the tool shown in ,Fi gures, 5, ,,6, and 'l.

This tool I5 is formed of suitablehard 'metal stock'and is constructed and arranged to provide a pair of substantially cylindrical surfaces J], which are arranged converging toward each other and are formed on radii substantially identical to "1 the radius of the lifting column withwhich the, lifting plate is subsequently 'tobe associatedgaii'd which radius is, therefore, substantially identical with the radius of the aperture l2 formed in the lifting plate II]. This teens:foreed'intotheaw erture l2 and obviously will engage theinterior surface of the aperture inthe liftingplate' at the point of intersection of the counter-es'ink and'athe cylindrical portion of the aperture. As this toolisforced into the lifting plate, H2 in themanner illustrated in Figure 4, it will serve to,;crush ..the metal of the lifting plate to form relatively small but well defined areas [8 on eachof the-opposite sides of the aperture I2. In view of the fact that the tool !5 is provided with the cylindrical surface portions ll, it will be apparent that these cylindrical surface portions I! will form the surfaces l8 of the lifting plate so that they will lie ina cylindrical surface-defined by introducing the lifting column 20 into the aperture l2 and inclinin'g' its axis at the'angleu'of convergence of'the tool l5. 1 a I 4' In accordance with the present method, the tool I 5 may first be inserted from "one side of the lifting plate to form the surfaces l8 and'subs'equently inserted from the opposite side to form similar surfaces 22, or a pair oftools similar-to the tool l5 may be simultaneously inserted'into the aperture of the lifting plate fromopposite' sides. In any event, the lifting plate in itsifinal form will have the conical surfaces [8 and-.22

formed therein adjacent vopposite'axial ends of the aperture [2.

It will be readily appreciated that the countersinking operation performed prior to the last described operation serves to provide an obtuse angled surface which gives support for. the metal at the point of intersection of the counter-sink and the surface portions l8 and 22 of the aperture and thus prevents forming a burr on .either'the upper or lower surfaces of the plate and permits accu' rate formingof' the interior of the aperture.

It will be readily appreciated that when a lift"- ing plate has been completely formed and .is provided with an aperture having an interior configuration as the aperture shown in Figure'4 or the drawing, this lifting plate may be mounted on a lifting column as is shown in Figure 2 of the drawing and that when the lifting plate is tilted at a slight angle to the perpendicular with respectto the axis of the lifting column 20, one of the sur faces l8 on one side of the aperture and one of the surfaces 22 on the opposite side of the aperture will smoothly and frictionally engage the surface of the lifting colunm thereby locking the plate in predetermined position with respect to the column. In this way, the load carried by the lifting plate is distributed throughout a small but preeisely defined area which area has aconfigur'ati-on such that substantially all points within the "area will lie in a cylindrical surface common to, bo'th the column and the interior surface of the lifting plate thereby materially reducing the unit pressure which would be encountered in the event the sharp corners of the counter-sink were pern'li ttedtodirectly'engage the surface of the lift- 'fiingicolumn.

' It will still'further be appreciated that the forjmation of the areas" [8 and the areas 22 makes the lifting plates perfectly symmetrical so that it is entirely immaterial whether they are assembled right-iside-up or up-side-down with respect to the lifting column with which they are to be associated; The construction described also obviously serves to preclude-the possibility of the sharp corners of the aperture deforming the surface of the' lifting column and from the very first permits smooth, satisfactory operation of the lifting plate mechanism with respect to the column.

It .will'be readilyappreciated from the foregoing that the'above described construction is one which is exceedingly simple and cheap to manufacture. Themethod performed is simply, easily,

and ;cheaply practiced, and the tool used for performing the methodis unique and at the same 'time'che'ap and simple.

It will be readily apparent to those skilled in the art that manyother' and further modifications of the structure above described may be made yet at the same time falling within the scope of the invention as defined in the ubjoined claims.

1 What is claimed 1 '1.'A lifting plate for friction type elevating mechanisms, comprising a metallic member having an aperturetherethrough, the axial central portion of said aperture having walls. lying in the surface of al'cylinder whose axis is normal to the plane 'of said plate, and zones adjacent said cylindrical surface lying in the surfaces of cylinders whose axes are inclined to the axis of said first mentioned cylinder.

a 2'. A lifting plate for friction typeielevating mechanisms, comprising a plate-like member having an aperture therethrough, the axialcentral zone of said aperture having walls lying in the surface of a cylinder whose axis is normal to the plane'zofqsaid plate-like member, the axial ends of saidaperture being countersunk, the walls of said aperture on each side of said plate having a pair of zones lying between said counter-sink and said cylindrical zone, which lie in the surface of cylinders whose axes are inclined to the axis of said first mentioned cylinder.

.EARL G. GUNN. 

